Agilent Technologies B1500A Training Manual page 110

Low Current Gate Oxide Meas.
Using Guarded Chuck
SMU1
Gate Oxide Capacitor
This is a simplified block diagram of the prober requirements for a guarded chuck connection. When
implemented properly, very fast low level sweeps are possible due to the elimination of stray
capacitance at the probes (wafer top side) as well as in the chuck (wafer bottom side).
Chuck
10^13 ohms
Chuck Guard
10^13 ohms
Shielding Box (Ground)
6-38
Module 6
Low Current Measurement
SMU2